you could make the badge (or whatever notification is used) optional

I thought about suggesting that, but I'm not sure the badge would have any meaning if not used consistently. I don't know.

I had an idea that I would be happy with personally, but don't think it would fly since groups.io is a for-profit (or eventually for-profit;) business: the badge might say "This group contributes to groups.io" or something along those lines.  
--
J

Messages are the sole opinion of the author. Especially the fishy ones.

I wish I could shut up, but I can't, and I won't. - Desmond Tutu